97L a major rainfall threat; October hurricane outlook; NC rains finally end

A large and complex region of disturbed weather (Invest 97L), centered about 800 miles east of the Lesser Antilles Islands, is headed west-northwest at 15 - 20 mph and will bring heavy rain showers and gusty winds to the northern Lesser Antilles Islands on Saturday and Sunday. Wind shear is a moderate 5 - 15 knots over 97L, and the waters beneath are very warm, 29°C. However, recent satellite imagery shows that the intensity and areal coverage of 97L's heavy thunderstorms have decreased this morning, thanks to some dry air being ingested into the storm. The SHIPS model predicts that wind shear over 97L will rise to the high range, 20 - 30 knots, Saturday through Tuesday, but some of the global computer models depict only moderate amounts of shear for 97L during this period. The NOGAPS model is the only model currently showing significant development 97L, and that model predicts 97L will be near Puerto Rico on Monday, the Dominican Republic on Tuesday, Haiti on Wednesday, and Eastern Cuba and the southeast Bahamas on Thursday. NHC is giving 97L a 40% chance of developing into a tropical depression by Sunday, but as of this morning, had not tasked the Hurricane Hunters to fly into the storm over the next two days. 97L will slow down to 5 - 10 mph on Sunday, bringing the potential for an extended 3 - 4 day period of heavy rains for the islands in its path. Even if 97L does not develop into a tropical depression, its slow motion may result in life-threatening flash flooding and mudslides in Puerto Rico, the Dominican Republic, Haiti, and eastern Cuba next week.

Figure 1. Morning satellite image of Invest 97L.

October hurricane outlookOctober is here, and it is time to take stock of where we stand and how far we have to go before hurricane season is over. The beginning of October traditionally marks the two-thirds point of hurricane season; approximately one-third of all hurricanes and 28% of named storms occur after October 1. Tropical Storm Nicole brought us up to fourteen named storms for the year, and I expect about 4 - 5 more named storms this year with 2 - 3 of these being hurricanes. That would add up to 18 - 19 named storms for the season, putting 2010 in 3rd - 5th place all-time for most named storms. Since record keeping began in 1851, only four seasons have finished with more than eighteen named storms. These seasons were 2005 (28 named storms, with the 17th named storm, Rita, occurring by October 1); 1933 (21 named storms, with the 18th named storm occurring by October 1;) 1995 (19 named storms, with the 15th named storm, Opal, occurring by October 1;) and 1887 (19 named storms, with the 10th named storm occurring by October 1.) The most likely time to get activity is during the first two weeks of October. There are still two weeks of peak hurricane season left before the activity traditionally begins to decline steeply (Figure 2.) Given the record warm sea surface temperatures in the Atlantic this fall, the presence of La Niña in the Eastern Pacific keeping wind shear lower than average, and the observed increase in late-season activity in recent decades, I expect this year's peak portion of hurricane season will last until the end of October. I predict three named storms, two hurricanes, and one intense hurricane will form in the Atlantic this month, with two named storms and one hurricane occurring in November - December, making 2010 as the third busiest Atlantic hurricane season of all-time.

Figure 2. Climatological frequency of Atlantic named storms and hurricanes.

Jamaica cleans up after NicoleTropical Storm Nicole lasted only six hours as a tropical storm, but the storm's torrential rains hit Jamaica hard. Nicole's rains killed at least six people on the island, and at least thirteens others are missing and feared dead. The storm cut power to 170,000 island residents, and caused millions of dollars in damages. Wunderground member JamaicaZed wrote me to say his rain gauge in the Kingston suburb of Norbrook caught 17.39" of rain Monday through Thursday, with 11.10" coming on Wednesday.

Historic rainfall event for eastern North Carolina ends The rains have finally ended In North Carolina, where tropical moisture streaming northward in advance of Nicole generated a historic rainfall event this week. Wilmington, NC set records this week for the heaviest 3-day, 4-day, and 5-day rainfall events in city history, and the month of September ended up as the second rainiest month ever recorded in the city. A remarkable 22.54" of rain fell on Wilmington during the 5-day period Sunday through Thursday. The previous record was 19.06", set in September 1999 during Hurricane Floyd. Fortunately, eastern North Carolina was under moderate drought conditions prior to this week's rainfall onslaught, with just 0.18" of rain falling during the first 25 days of September. Only minor to moderate flooding is occurring on North Carolina rivers, with just one river, the Northeast Cape Fear River near Chinquapin, expected to experience major flooding. Portlight.org is beginning to identify needs in Eastern North Carolina in the wake of the flooding, and expects to perform the first deployment of their new relief trailer within the next few days and send a truck loaded with water, food and personal hygiene supplies.

The most remarkable thing about Wilmington's second-wettest month in history is that it came without a hurricane affecting North Carolina. All four of the other top-five wettest Septembers in history were due, in large part, to hurricanes:

Figure 3. Radar-estimated precipitation for North Carolina since Sunday shows that the precursor moisture from Nicole has brought widespread rain amounts of fifteen inches (white colors.)

Heavy rains and flooding for New EnglandThe plume of tropical moisture that affected North Carolina is now triggering heavy rains in New England, and flood warnings are posted throughout most of New Jersey, eastern Pennsylvania, eastern New York, Delaware, and Vermont this morning. In New York City, heavy rains this morning have overwhelmed one section of the city's subway system, and flooding closed several key road arteries in the city, snarling the morning commute. About two inches of rain have fallen so far this morning in the city. Severe weather is not expected, and no tornadoes were reported yesterday in association with this weather system.

Elsewhere in the tropicsDisturbed weather continues in the Central Caribbean, where the remnants of Tropical Storm Nicole will bring isolated heavy rain showers today to Hispaniola, Jamaica, Cuba, the Cayman Islands, and northern Honduras. The GFS model predicts this activity will concentrate near Hispaniola over the weekend, then push northwards into the Bahamas, with a subtropical or extratropical storm forming over the Bahamas on Sunday or Monday. This storm could bring 2 - 4 inches of rain to the Bahamas Sunday and Monday. The storm will then move north-northeastwards, parallel to the U.S. East Coast, and not affect any other land areas. Several of the models are predicting the formation of a tropical depression in the Mid-Atlantic 5 - 7 days from now, in a location that would not be of any danger to land areas.

Quoting CaptnDan142:True, and it could very well happen again. The only seasons we can be sure about are the ones in the history books, or in this day and age - Wikipedia.

With all that potential in the Carib, Nicole never could get it together. Never got wrapped up. Maybe that will be what we see this month too.

With the dry air over the Gulf, and the chilly nights following temperate days around here, at least the northern GOM is shutting down fast. I think we'll see that start spreading south.

In a way, it would be good to see a couple more to dissipate some of that heat. Problem is, where the heat is, there's no way outta there without running over somebody. Just not all that convinced it'll actually happen.

If we only had some big tunn.... erm, fergit it. ;-)

Perhaps, but I strongly doubt Nicole was our last. The Doc's much more bold than I am even, 4-5 he thinks.

Quoting NRAamy:Jerry...it's a good thing you make the best ice cream in town....otherwise, Ted Nugent would be paying a visit to your home.... And it ain't to play Cat Scratch Fever on your Guitar Hero WII system.....

I've met Terrible Teddy; a band I was in opened for for him at a festival thing in the 70s...Teddy's easy; YOU scare me

Too much energy and close proximity to get anything to bundle and consolidate into anything other than a TD or weak TS. It's probably why the GFS shows like 50 weak LP's spinning around out there and doing nothing significant. If it wasn't for this monsoon pattern the Caribbean could spit out plenty of decent canes with the heat content down there. I just don't see a decent storm in the making until this pattern changes. That could be a while and by then it could be too late. These monster deep troughs don't help matters as well bringing dry cooler air further to the S.

I disagree. And I haven't seen much of a cool down either, nor has the Caribbean for that matter. We'll crank out 2 more at least. 2008 did, cranked out two more major hurricanes and this season is more active than that, and much more warm.

True, and it could very well happen again. The only seasons we can be sure about are the ones in the history books, or in this day and age - Wikipedia.

With all that potential in the Carib, Nicole never could get it together. Never got wrapped up. Maybe that will be what we see this month too.

With the dry air over the Gulf, and the chilly nights following temperate days around here, at least the northern GOM is shutting down fast. I think we'll see that start spreading south.

In a way, it would be good to see a couple more to dissipate some of that heat. Problem is, where the heat is, there's no way outta there without running over somebody. Just not all that convinced it'll actually happen.

Sigh, I see Kerry has made his fearless prediction. He's only half-true. Troughs of low pressure cause systems and anything to go northeastward in the Caribbean, so Mobile eastward isn't done yet. Once something gets down there, it's game on. As much as moisture can cause anything to form.

Quoting StSimonsIslandGAGuy:This has to be the slowest blog since tropical season began. What do you think the odds are that 97L will ever be named a tropical storm? Not just in the next 48 hours, but ever.

its gonna slow down a lot more as for 97 rain rain rain and maybe more rain i think most of whats left will in fact be high rain events from here on till the end

Quoting robert88:Nothing but a big mess out there. All i see is a monsoon trough that stretches from the Caribbean to the central Atlantic with several lows fighting it out. Cool dry air and high shear will be making it into the GOM and off the EC. The jet flow could make it as far S as the NW Caribbean and Bahamas. I don't see much happening imo.

When things were going hot and heavy for a while in September, I thought so too. But then it degenerated into that sloppy mess Nicole, and the cool-down we have had here in the south... I just don't see it happening.

I disagree. And I haven't seen much of a cool down either, nor has the Caribbean for that matter. We'll crank out 2 more at least. 2008 did, cranked out two more major hurricanes and this season is more active than that, and much more warm. Heck, last year cranked out a Category 2 in November! That was a insane cold season for the south!

Nothing but a big mess out there. All i see is a monsoon trough that stretches from the Caribbean to the central Atlantic with several lows fighting it out. Cool dry air and high shear will be making it into the GOM and off the EC. The jet flow could make it as far S as the NW Caribbean and Bahamas. I don't see much happening imo.

What made you think that was likely at all we wouldn't see Otto this year. Heck, this year will probably see Paula and Richard.

When things were going hot and heavy for a while in September, I thought so too. But then it degenerated into that sloppy mess Nicole, and the cool-down we have had here in the south... I just don't see it happening.

Quoting KerryInNOLA:To my fellow Gulf Coast neighbors. We made it thru the meat of the season. It's Oct 1st and our shields are up at 100% force. The 10 day forecast is for clear and cool. Nothing is on the horizon. We can safely drop our guards for the next 2 weeks with a reevaluation then for declaring the Northern Gulf season over if the fronts keep coming. Laissez le bon temps rouler!

Ours have been up for the 21 years I have been here. We have the biggest copper-top battery you ever saw. It's all in the power source.

a little early ya think normally numbers for the next season come out next season and when current season ends if the setup i see at the moment continues the season may be done except for maybe a couple of carb systems trackin nne that may pop up and any of the last eastern waves that are coming off africa which ends real soon also sst's have begun the downward turn as well except in the carb.with 59 days remaning in the season it will not be long now till we get to the 200 post mark in the blog in 24 hour period and settle in for the long quiet winter ahead on the blogs

But....but.....what about Global Warming blogs?

I don't see anything in the GOM for the next 7 to maybe 10 days. You may be right with the season winding down.

Quoting TropicalAnalystwx13:I see people giving out their 2011 Atlantic Hurricane Season.

What the heck...I'll give mine.

12-16........................ Named Storms6-9...........................Hurricanes3-5.......................... Major Hurricane Hurricanes

a little early ya think normally numbers for the next season come out next season and when current season ends if the setup i see at the moment continues the season may be done except for maybe a couple of carb systems trackin nne that may pop up and any of the last eastern waves that are coming off africa which ends real soon also sst's have begun the downward turn as well except in the carb.with 59 days remaning in the season it will not be long now till we get to the 200 post mark in the blog in 24 hour period and settle in for the long quiet winter ahead on the blogs